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Minimal clinically important differences in average, best, worst and current intensity and unpleasantness of chronic breathlessness

Ekström, Magnus; Johnson, Miriam J; Huang, Chao; Currow, David C

Authors

Magnus Ekström

David C Currow



Abstract

Background: Chronic breathlessness has devastating consequences. The minimal clinically important difference (MCID) for current intensity has been estimated as 9mm on a 100mm visual analogue scale (VAS). We aimed to determine MCIDs for commonly used dimensions and recall periods: the current unpleasantness and current, average, best and worst intensity of the last 24h for chronic breathlessness.

Methods: This was a secondary analysis of a randomized controlled trial of morphine vs. placebo during seven days in people with chronic breathlessness from severe disease. The breathlessness scores were self-reported using a diary each evening on 100mm VAS. The MCID for improvement in each score was estimated using anchor based and distribution based methods.

Results: 283 participants (mean age 74.2 years; 63% males; 58% COPD; 87.0% mMRC 3–4) were included. Anchor-based MCIDs for breathlessness scores ranged from -13.9mm to -9.5mm. The MCIDs were similar when using different anchors and across all participants, and participants with more severe breathlessness (mMRC 3–4), respectively. Distribution based effect sizes were: small (-4.7 to -6.3mm), moderate (-9.4 to -12.5mm) and large effect (-15.0 to -20.0mm). Sample sizes for trials using the different scores were proposed. MCIDs of absolute change were more stable than using relative change from baseline.

Conclusion: An improvement of about 10mm on a 100mm VAS is likely to be clinically meaningful across commonly used measures of chronic breathlessness (current intensity, unpleasantness, and average, best and worst intensity over the last 24h) – to evaluate clinical benefit and effects in therapeutic trials.

Journal Article Type Article
Publication Date 2020-01
Journal European respiratory journal
Print ISSN 0903-1936
Publisher European Respiratory Society
Peer Reviewed Peer Reviewed
Volume 55
Issue 5
Article Number 1902202
APA6 Citation Ekström, M., Johnson, M. J., Huang, C., & Currow, D. C. (2020). Minimal clinically important differences in average, best, worst and current intensity and unpleasantness of chronic breathlessness. European respiratory journal, 55(5), https://doi.org/10.1183/13993003.02202-2019
DOI https://doi.org/10.1183/13993003.02202-2019
Publisher URL https://erj.ersjournals.com/content/early/2020/04/20/13993003.02202-2019
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